x86, espfix: Make it possible to disable 16-bit support

[pandora-kernel.git] / arch / x86 / kernel / entry_64.S

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index bffaa98..da0b9bd 100644 (file)
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1045,8 +1045,10 @@ irq_return:
         * Are we returning to a stack segment from the LDT?  Note: in
         * 64-bit mode SS:RSP on the exception stack is always valid.
         */
+#ifdef CONFIG_X86_ESPFIX64
        testb $4,(SS-RIP)(%rsp)
        jnz irq_return_ldt
+#endif
 
 irq_return_iret:
        INTERRUPT_RETURN
@@ -1058,6 +1060,7 @@ ENTRY(native_iret)
        _ASM_EXTABLE(native_iret, bad_iret)
 #endif
 
+#ifdef CONFIG_X86_ESPFIX64
 irq_return_ldt:
        pushq_cfi %rax
        pushq_cfi %rdi
@@ -1081,6 +1084,7 @@ irq_return_ldt:
        movq %rax,%rsp
        popq_cfi %rax
        jmp irq_return_iret
+#endif
 
        .section .fixup,"ax"
 bad_iret:
@@ -1152,6 +1156,7 @@ END(common_interrupt)
         * modify the stack to make it look like we just entered
         * the #GP handler from user space, similar to bad_iret.
         */
+#ifdef CONFIG_X86_ESPFIX64
        ALIGN
 __do_double_fault:
        XCPT_FRAME 1 RDI+8
@@ -1177,6 +1182,9 @@ __do_double_fault:
        retq
        CFI_ENDPROC
 END(__do_double_fault)
+#else
+# define __do_double_fault do_double_fault
+#endif
 
 /*
  * End of kprobes section